It's not possible to have a Business account on Sandbox; it's not supported. You'll have to create a new Business account on Production for testing purposes if you want to test in an account separate from your real production account.

What I would do is take any notes from your personal account that you think you'll want to be sharing with your colleagues, and move them to the business account. (In the Mac client - I believe I recall you use a Mac - you can Cmd-click and Shift-click multiple notes and then choose "Move Notes to..." to get them over to the business side. You can't move a whole notebook so you have to use this move-notes method.)
Then I would keep using the personal account for your own stuff that you won't be sharing.
One of the disadvantages of the split, sometimes, is searching - you have to do separate searches if you're looking for the search term in both sides (although the desktop client makes it easy to do the same search in the other side by providing you that option at the top of the notes list). I say sometimes because at times the split can be an advantage instead. For example, if I search in my personal account for my wife's name "Diane", I'm happy that I don't see notes in my business account with "Diane" in them because they will definitely not be what I'm looking for.
One good thing about having a personal account is that, if you email notes into Evernote using the email address they provide you, you can only email into a personal account - there's not at present a capability to email into your business account (though it's definitely been requested).
Let me know if you have any questions about the above, or anything else Evernote-related!

Hi Michael,
(Have followed you for years, happy to hopefully be able to "give back".)
Taking your last question first, you can't really get rid of your personal account, because for the moment at least, an Evernote Business account requires a connected personal account.
Having said that, the question is, does it make sense to move all of your personal notes over to your business account?
I think it largely depends on the degree of conceptual separation between the notes you have in personal and what you're now starting to put in business. In order to provide useful advice, can you tell us a bit about why you decided to start an Evernote Business account and what you plan to use it for?

I'm going to guess you're using the Windows client. You're correct, AFAIK there's no way to import directly into a Business account on Windows.
The Mac client does allow you to import directly into a Business notebook.

I know it's a hack but one solution is that when you Send a Copy, use the CC me on this email option (once you check it, that choice will remain sticky so you don't have to remember to check it every time); then write a rule in your email client which moves those emails into a folder called something like Emails Sent from Evernote.

Yes, you do it via the Admin Console. Click "Notebooks" in the left panel. Use the checkmark field to the left of the notebook's name to select one or more notebooks, then drop down the "Actions" menu (at the top of the notebooks list) and select "Delete Notebook(s)".

@DaveH24 The first thing to check is to make sure the notes you're working with are really what Evernote considers as official "contact cards". To do that, go to the notebook in question and put this in the search box at the top of the view:
contentClass:evernote.contact.1
When you do that, do you get the notes you're expecting to see as contacts?

@NRobinson and @DaveH24 - I've posted an update to ContactExporter; please give it a go and see if your issues are fixed. You should get notified to download and install the update when you launch the program. It's also available for download here.

@NRobinson Thanks for sending the ENEX file. I've located the issue and am working on a fix - stay tuned.
@DaveH24 I'm not sure what your specific issue is but it may well be the same root cause as with @NRobinson - so the best thing is probably to try the new version once I get the fix made and posted, and see if that fixes it for you, too. If not, we can explore further.

As @rezecib says, the API calls for Spaces haven't been added to the public Evernote API. Not sure if/when they will be. But notebooks exist as primary elements in the Evernote store, independent of whether they are attached to a Space or not. So you should be able to access notebooks via the API, but subject of course to access restrictions.
As @rezecib asks, what specifically are you wanting to do? (Technically we're supposed to be having developer discussions in StackOverflow but I'll go with this thread until someone says otherwise.)